The American Dental Association Council on Scientific Affairs recommended in December 1995 that industry and the research community undertake an aggressive and ambitious product development program to improve the water quality from dental units. It declared that by the year 2000, water delivered to patients during non-surgical dental procedures should consistently contain no more than 200 colony forming units per milliliter of aerobic mesophilic heterotrophic bacteria at any point in time in the unfiltered output of the dental unit. The impetus for the ADA statement was the concern in the scientific community about the rising incidence of infectious disease among patient populations, the high incidence of immuno-compromised patients that dentists were treating, and the realization that water coming from dental units is less than the standard for potable drinking water. The potential for cross-contamination existed and there was fear that patients were being subjected to risk during routine dental procedures. Research showed that there were two causes of bacterial contamination in the dental water lines. The first was the persistence of biofilm, a build-up of bacterial colonies (plaque) which adhered to walls of the tubing. The other was back-flow of bacterial laden fluids from the dental handpieces and water syringes, a result of reversal pressures or diffusion or backgrowth of the bacterial contaminants. It has been long known that Legionella pneumophila, the infective agent of Legionnaire's disease, was prevalent in contaminated water supplies. However, a most alarming report was that dental professionals had a significant occupational exposure to Legionella from aerosolization of dental unit water. This was confirmed by the high levels of anti-Legionella antibodies found in their blood. A mild, self-limiting form of Legionella disease, Pontiac fever, was the most common illness. But, there is one report of a dentist who died after contracting Legionella pneumonia from his own contaminated dental waterlines. Based on these facts, the implications for public health are very serious.
To date there have been few viable solutions to this problem. Biofilm is resistant to removal and the agents that have been used are either caustic, corrosive, toxic or damaging to patients, staff personnel, equipment or the environment. The remedies that are available are either not completely effective or they damage dental devices, dental components and parts, and/or dental water units.
Aside from the ADA there are regulatory agencies that are involved in this issue. The Occupational Safety and Health Agency (OSHA) has proposed regulations which require the elimination of hazardous bio-aerosols in the workplace, including dental offices. Because of the prevalence of Legionella in dental water lines, OSHA pressure will cause a strong demand for a solution to the problem. Moreover, as media focus becomes more acute, public awareness will stimulate the dental profession to introduce new systems and protocols for waterline decontamination.
The Food and Drug Administration (FDA) has already cleared several devices for water line contamination. They are enabling rapid review and clearance of new products under the 510(k) filing process.
There remains a need for an improved asepsis apparatus and method for the dispensing of a disinfectant solution safely in order to clean and decontaminate the biofilm and the microbial contaminants within water, air and vacuum systems, as well as water, air and vacuum lines in dental and medical systems. Additionally, the asepsis apparatus should easily and automatically supply a predetermined amount of disinfectant solution to the dental equipment (i.e. water system) during the non-working hours (night time) at the dental facility.